HTC 2498 isn’t letting the recent struggles of its One series keep it down, as the company is reportedly prepping a sequel to the HTC One X for an early fall release. An unnamed source has told Stuff that the new HTC smartphone — codenamed the “Endeavour C2″ and likely to be officially called the HTC One X+ once it’s released — will feature a 1.7GHz quad-core processor, an “improved” battery and full compatibility with all of the One X’s accessories. The “Endeavour C2″ has been tagged for a September release, meaning HTC will likely announced it around the same time that Nokia NOK announces its first Windows Phone 8 smartphones and Apple AAPL announces its next-generation iPhone.